The glute ham developer’s primary function is a glute ham extension which is an exercise performed with a knee pivot, the exercise isolates the glutes and hamstrings.Compare this to the roman chair’s primary function which is a back hyperextension with a hip pivot.The Glute Ham machine has way more travel for the foot rollers both vertically and horizontally.Also, it has much larger thigh pads, allowing for increased range on all exercises.A glute ham can do everything a roman chair can do but not the other way around.